1. Field of the Invention
The field of the invention is the petrochemical industry, and more particularly, the cleaning of fin tubes in heat exchangers.
2. Description of Related Art
The term “heat exchanger” as used herein refers to certain apparatus in common use in the petrochemical industry. Typically, a heat exchanger receives hot crude oil from a fractionating tower, the oil then being routed through the fin tubes. Boiler feed water is presented inside the exchanger in areas surrounding the fin tubes. The heat exchange between the hot crude oil and the boiler feed water provides steam and reduces the temperature of the crude oil, the cooler crude oil is then transferred from the heat exchanger for additional processing elsewhere. The drop in the crude oil temperature typically results in carbonate scale buildup within the fin tubes.
A first example of a prior art heat exchanger 10 (with fin tubes in a “U” configuration) is depicted in FIGS. 1–3, with FIG. 3 depicting a plan view of some of the fin tubes in the area of the “U,” and FIG. 2 depicting a side view of the same area. In this type of heat exchanger, both ends of each fin tube are presented at the openable end of the exchanger, providing access for the insertion of the fluid discharge end of a typical high-pressure cleaning apparatus. A typical cleaning tool is a line mole having a flexible hose with a discharge tip. Such fin tube ends will typically be presented in a substantially uniform pattern across the opened end of the heat exchanger when viewed from the end. Cleaning fluid entering one end of a fin tube on the right side of the opened heat exchanger end will be discharged, along with discharged material, at the fin tubes' second end on the left side of the opened heat exchanger end.
A second example of a prior art heat exchanger 20 (with fin tubes in a straight configuration) is depicted in FIGS. 4–5. In this type of heat exchanger, the ends 22,23 of the heat exchanger can be removed to present one end of each fin tube at the first end 26 of the heat exchanger shell 28 (frame), and a second end of each fin tube at the second end 27 of the heat exchanger frame. Cleaning fluid discharged into a fin tubes first end, at the first end of the heat exchanger frame, will be discharged from the second end of the fin tube, at the second end of the heat exchanger.
The fin tubes in both heat exchangers 10,20 typically have one-half inch inside diameters. Each fin tube has exterior fins about its outside circumference, the fins being spaced by approximately one-sixteenth inch.
A significant operational, safety and regulatory concern related to the cleaning process for these types of heat exchangers is the cleaning fluid and dislodged material being discharged on to the surrounding equipment or the ground. Operators have attempted to isolate the area subject to splashing and exiting fluids and dislodged materials, by temporarily isolating and/or covering the area using sheets of plywood, etc. All current methods of controlling the splashing and exiting fluids and dislodged materials are labor and material intensive, making the process time consuming and expensive.
Equipment is needed that will install quickly and capture the splashing and exiting cleaning fluids and dislodged materials while the heat exchanger fin tubes are being cleaned.